348 CLARK. G.M. ET AL.

ORIGINAL ARTICLES

MULTIPLE-CHANNEL COCHLEAR IMPLANTS FOR CHILDREN: THE MELBOURNE PROGRAM

CLARK, O.M., DAWSON, P.W., BLAMEY, P.I, DETTMAN, S.J., ROWLAND, L.C., BROWN,A.M., DOWELL, R.C., PYMAN, B.C., WEBB, R.L.

Australian Bionic Ear and Hearing Research Institute, Human Communication Research Centre, University of Melbourne and Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne. Although there have been 300 years of deaf education, may be taught the Australian version of of profoundly-totally deaf children today on average are not the deaf (). In the case of signed English, the signs able to reach the same level of achievement as their represent individual words as well as conveying grammatical normally hearing peers (Geers & Moog, 1989). This failure information such as tense. This form of signing is used in of deaf children to develop their true potential is largely total communication. and although it is difficult for due to the difficulty they have in communicating with children to attend to the speech signal by the auditory/oral normally hearing people. During the last 300 years there mode at the same time as signed English, they can develop have been basically two different methods of education the skills to communicate by either one used separately. used (The New Encyclopaedia Britannica, 1983). Firstly, In the case of the sign language of the deaf, the one which maximises auditory and lip reading cues grammatical structure is quite different from the structure (auditory/oral), advocated by Juan Pablo Bonet (1620), and of English. In practice, this method makes it difficult to one which uses a series of signs to convey meaning learn written language, and is not appropriate for (signing), developed by Charles-Michel (1712-89). In combining with an auditory/oral method of education. addition, there is a method which endeavours to combine As the multiple-channel cochlear implant provides both auditory/oral and signing approaches called total information by stimulating hearing sensations, it is communication. In practice, however, children taught by optimally used by combing these auditory signals with lip total communication tend to receive speech more reading cues. Consequently, children receiving a cochlear predominantly by one or other of these methods. implant should ideally be educated using an auditory/oral Within the two main methods are variations. For method. example, with the auditory/oral system some educators prefer to teach by combining auditory information with lip reading cues while others endeavour to get children to Management Team develop their listening skills by withholding visual information (the auditory/verbal method). A further In managing a child for a cochlear implant we consider variation of the auditory/oral method is to use cueing that a team approach is essential. The management team supplements. In this situation the child is helped by is outlined in Figure l. The team consists of otologists, providing additional visual cues when speech sounds look audiologists, speech pathologists, educators of the deaf, the same on the lips. There are also different approaches and consultants in psychology, child psychiatry and social to training with the auditory/oral schemes. On the one hand, educators may emphasize training in listening to segments of speech and speaking in very structured - Otologists situations. On the other hand, they may emphasize learning conversational speech in more natural and unstructured - Audiologists ways similar to that which would occur with normally - Speech pathologists hearing children. - Educators of the deaf In the case of signing there are basically two different - Consultants systems: children may be taught signed English, or, they - Psychologists - Child psychiatrists Correspondence: - Social workers Professor Graeme M. Clark, Royal Victorian Eye and Ear Hospital, FIG. 1. Management team personnel; cochlear implants for children. 32 Gisborne Street, East Melbourne. Victoria 3002

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CLARK, G.M. ET AL. 349

work. The team also requires a leader who is co!1versant establishing the hearing threshold levels and determining with most aspects of the program. Furthermore, there is how effective the hearing aids are. Establishing the hearing a need for very good liaison between members of the team thresholds in very young children is facilitated by using a based in a hospital and the teachers in the school. The team steady state evoked response (SSEP) technique we have is responsible for the following areas in a cochlear implant developed in the Department of Otolaryngology (Rickards child's management: preoperative evaluation and selection; & Clark, 1984). This technique involves presenting parent counselling; surgery; auditory training in speech amplitude modulated (AM) and/or frequency modulated production, language and auditory perception and (FM) sounds with different carrier frequencies. A Fourier audiological assessment. These responsibilities are listed analysis is carried out on the evoked responses, and in Figure 2. objective criteria are set for establishing thresholds at each caI'Tier frequency. The thresholds are specific for the regions excited by the carrier frequencies. It is an especially useful procedure in measuring the thresholds for low frequencies - Preoperative evaluation and which can still be present when the high frequencies are selection lost. Assessing hearing thresholds at low frequencies is - Parent counselling difficult with standard ABR techniques, but can be successfully carried out using the SSEP procedure referred -Surgery to above. - Auditory training In stages 3 and 4, we assess all aspects of a child's ability - Audiological assessment to communicate. This means assessing speech perception, speech production, language skills and pragmatics (their ability to converse). Following this speech and language assessment, the FlG. 2. Management team - responsibilities: cochlear implants jar children undergo a preoperative training program so they children. can learn to use any residual hearing. This program also gets them used to the auditory/oral training they will receive when they get an implant. Preoperative Evaluation and Selection Finally, the assessment of the child is reviewed by the management team and ethics committee before The preoperative evaluation and selection process takes implantation. place in five stages. At any stage a child may be considered unsuitable for an implant, and may be referred for an alternative sensory aid. The stages are shown in Figure 3. Parent Guidance

SI8ge 1: Initial assessment We would like to emphasize that, preoperatively and Hisiory (pmllmlnary) Audlomolry postoperatively, the parents need counselling. This help ~ includes information on the procedure and discussion of Siage 2: AkdlCIIIllnve.llgatlons HI.tory (""ta/Ied) their emotions during both the preoperative and Physical examInation Radiology postoperative periods. The clinician has a responsibility to PromonlQfy sUmulatlon ...... r.!!-­ address with the parent such issues as the potential and Stage 3: AudJDIOfjlcaJ evaluations limitations of the device, the range of results obtained with E=:~:::'::':::i:S ~ Speech percepllon ttnlting Preoperative training. children who currently have the implant, the importance _~ Family support, Stage 4: SpeeCh and I8nguage evaluation, EducBti()(UIllia/son of factors such as motivation (the child's and their own), Speech production ...... :::t:J- and the effect of age at onset of deafness and current Language Pragmatic behaviour development of speech and language on the child's Stage 5:-""- Clinical review prognosis. Time is needed to help the parents understand --J!!!!I"'~ SUrgery and accept the effects of implantation. The time available PoatopIJrativs management before the operation is a valuable time for developing FIG. 3. Preoperative evaluation and selection; cochlear implantsjor rapport with the parent. children. Parents are also encouraged to have contact with parents of children who have already received the implant. This The first stage consists of an initial medical assessment, is accomplished through the Parents' Support Group which audiometric testing of hearing thresholds, and general meets on a six-weekly basis. This forum allows parents to counselling to ensure that the parents' expectations are develop friendships and sources of information: valuable realistic. support in times of need. Luterman (1979, 1984) notes that The second stage consists of a detailed clinical history the most valuable service a professional can give a parent and examination. We pay particular attention to middle ear is to put them in touch with other parents. The parents infections, as susceptibility to infection may delay or themselves recognise the value of sharing experiences and prevent implantation. A CT scan is carried out under emotions, and supporting each other. anaesthesia for young children. Electrical stimulation of An important component of the preoperative period is the promonotory is only done for children 10 years and preparing the child for the operation. The parents may be above. reluctant to talk with their child about the operation, In stage 3, the audiological assessment aims at fearing the child may become anxious about the events.

J. OTOLARYNG. soc. AUSTRAL., JANUARY 1991, 6, No.5 350 CLARK, GS1. ET At.

They need to be encouraged to discuss the events to ensure Surgery that the child is prepared for a hospital stay, an operation, a bandaged head and some pain. It is especially relevant The surgery is basically similar to that in the adult, but that the child knows his/her hair will be shaven, since this needs to be modified because the temporal bone is smaller will occur under the anaesthetic. This can severely affect and the bone is thinner. their self-concept immediately postoperatively, and they The first point to emphasize is that the incision needs need to have the opportunity to adjust to the idea to be the same size as in an adult, and therefore it will beforehand. Preparation for hospitalisation generally appear relatively larger. The second point is that it may be includes a visit to the children's ward a couple of weeks necessary to drill bone down to dura to make the bed deep before being admitted. Often the parent will take photos enough to accommodate the receiver-stimulator package. which can be incorporated into a special "hospital" book, The third point is that the lead wire should be fixed or pinned up on the wall at home. Some parents put up superiorly and not to the mastoid tip as the latter area a calendar with each of the steps marked on it so that the expands more rapidly during maturation. With regard to child can anticipate the day on which he/she goes to fixation, ensure that there is a redundant loop between the hospital. The clinician, child and parents also use the books package and fixation point, and another redundant loop designed and supplied by Cochlear Corporation to help the between the fixation point and round window. These child understand the operation. The children may also meet redundant loops are important in allowing for head growth with other children who have had the implant, and they so that there is no of the electrode in the cochlea can have the opportunity to play with a doll who wears or the receiver-stimulator package. a "speech processor" and the external parts of the device. To minimize the effects of head growth, we have been studying the growth of the temporal bone to find out where Despite this preparation, Hie clinician still needs to be we should place the ties (Shepherd et ai, 1989). One aware of the possible psychological effects on the child. important finding from the study is that the distance One child, an eight year old, refused to take her hat off between the round window and fossa incudis does not for weeks after the operation. Another refused for three change from birth to adult life. This is illustrated in Figure months to talk with the clinician who had visited him in 4. As a result of this finding we are now carrying out a hospital. Another disliked coming to the hospital for about clinical and experimental trial to see whether we can six months following hospitalisation and the start-up. adequately fix the electrode to the floor of the antrum in Everything should be done,to minimise these reactions, but the region of the fossa incudis. The tie is illustrated in it is not easy to predict how a particular child is likely to Figure 5 (Webb et aI, 1990). In addition, we leave a respond to the changes in his/her life - temporary loss redundant loop from this fixation point to the package to of hair, wearing the device, new auditory sensations, interest allow for temporal bone growth. in the device from other people, to name a few and each child's reactions need to be treated with understanding. ROUND WINDOW TO FOSSA INCUDIS VS AGE Prior to the signing of the consent form, the parent is continually being encouraged to weigh the pros and cons o TO 11 YEARS of having their child implanted. It must be stressed that the parent has the right to decide against the operation at 12-,------, 0 0 0 any time up until their child actually goes into surgery. 10 10 iD 0 0 0 Ultimately, the decision to go ahead with the operation or pm 0 0 g 0 0 not lies with the parent. However, the clinical team has the 5' elg 0 0 6 responsibility of deciding whether to recommend against ~ 6! a child being implanted. The involvement of the whole team " in formulating a decision regarding a particular child is ~ .I vital: only by sharing all aspects of the child's history and progress - medical, audio logic and communication can 2' ..... a full picture of the child's skills and potential be provided. 01 1 No decision for or against implantation can be made on 0 4 6 8 10 12 the basis of only one of these aspects. AfX ('r1:ARS) FIG. 4. (Shepherd e( ai, 1989) The distance between the round window Because the decision to implant is based on many factors, and fossa incudis versus age. it is often not until after a lengthy period of (re)habilitation that the clinical team can decide whether to offer the parents the option of the cochlear implant operation. This apparent indecision on the part of the clinic can be very Auditory Training and Education frustrating for the parents, who have possibly already decided for themselves that they want their child to receive Three weeks after their surgery the children are ready the implant, and want to get it over and done with as to have the stimulus thresholds and maximum comfortable quickly as possible. They require a great deal of support listening levels for each bipolar electrode pair mapped into during this time from a clinician who is willing to listen their speech processor. When presenting children with to their concerns, and who can provide them with electrical stimuli for the first time great care is taken to see information about the implant and their child's progress that they don't receive a stimulus that is too strong. (Rowland et ai, 1990a). Thresholds are determined by gradually increasing the

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FlG. 5. (Webb et ai, 1990) A diagram ofa platinum tie being placed l around the floor of the antrum in the region of the fossa incudis to hold the electrode array in place. The electrode is protected by a Silastic sleeve.

stimulus intensity and getting the child to respond in some way by, say, placing a block on a spike when they hear a sound. The maximum comfortable levels are determined by slowly increasing the intensity of a speech stimulus. while the child IS distracted at play, until they indicate that it is uncomfortable. When the speech processor is programmed for the child, we commence training, and endeavour to improve his/her speech perception, speech production and language skills. This is facilitated with the MSP speech processor recently released by Cochlear Pty FIG. 6. The WSP III speech processor (presentsfundamentalfrequency Limited. This is shown in Figure 6 beside the standard FO, first formant frequency - FI; second formant frequency ­ device. It is smaller and lighter and much more suitable F2), next to the MSP speech processor (presents FOIFJlF2 and high for children. It also performs better than the previous WSP frequency spectral peaks - HFSP). III processor (Dowell et al 1989, 1990). In training children to use the cochlear implant there are two main points to consider: firstly, the children should Child Aetiology Age at Age at Educational ideally be educated by auditory/oral methods. This means onset implantation program they should be taught by methods which maximize the use (yean) (ye"') of their new auditory information from the implant, and Meningitis 3.3 10.2 Auditory they should be taught to combine their auditory skills with 2 MeningitiS 3.0 5.5 Cueing supplement lipreading. It is less likely that an implant could be used effectively in a signing environment, especially with sign 3 Unknown Congenital 8.0 Cueing supplement language of the deaf (AusIan). The second important point 4 Meningitis 1.25 8.2 Auditory I Oral is that children with implants, as well as other deaf children, should be trained by speaking to them naturally using normal conversation. FIG. 7. A summary of aetiology of deafness, age at onset, age at implantation and educational program for our first four verbal children

Audiological Assessment Child Aetiology Age Age at Currently (March 1990) we have implanted 13 children of at onset implantation {y_s; (years) 12 years and under, as well as seven teenagers. In our group Meningitis 2.3 3.5 of 13 children there are five who are verbal and eight who are pre-verbal. The children who are verbal have sufficient 2 Maternal 0 5.3 language to carry out speech tests. The children who are Rubella pre-verbal do not have language for standard speech testing. Our children are at different stages of assessment and we 3 Maternal 0 6.7 present the results for the first four verbal (Figure 7) and Rubella first three pre-verbal children (Figure 8). The results for BKB (Bench-Kowal-Bamford) sentences and AB (Arthur Boothroyd) words for cochlear implant FlG. 8. A summary of aetiology of deafness, age at onset and age plus lipreading, he~ring aid plus lipreading, and lipreading at implantation for our first pre· verbal children.

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352 CLARK. G.M. ET AL.

'80 r------~------~------E~trie.1 8; vision 45 • BKB Sentence, 80 1------­ • HearIng 40 1------+-----f-.-I!;!liJiIiI-+------<. ASW.... &; II'lalon .c .. It-~----~----- • VillOn • 60 aIon. '0 4. ,s ... " ,,.. 20 '0

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FIG. 9. The BKB sentence scores for our first four verbal children FIG. I/. Open·set word and sentence test score for our first four verbal for: lipreading alone. and hearing aid plus lipreading - preoperatively; children using electrical stimulation alone.

and lipreading alone, and cochlear implant plus lipreading ­ r------~~~~------~ postoperatively.

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CNIcI , CIIlId2 Child 3 CI\lId4 FIG. 12 (Busby et aI, 1990) Receptive vocabulary scores for verbal child I: observed scores versus age appropriate expected scores during FIG. /0. The AB word test () scores for our first four verbal pre and postoperative data collection limes. children for: lipreading alone. and hearing aid plus lipreading ­ preoperatively; and lipreading alone, and cochlear implant plus Finally, initial results for our first three pre-verbal lipreading - postoperatively. children are presented. One method of assessing them is to measure the number of times they communicate with alone for the four verbal children are shown in Figures 9 a sound or word rather than a gesture. The results for the and 10. The performance for hearing aid plus lipreading three pre-verbal children are shown in Figure 13 (Rowland and lipreading alone were tested preoperatively, and the et ai, 1990b). performance for cochlear implant plus lipreading and lipreading alone, postoperatively. The most obvious finding

was a significant improvement in scores for the cochlear &0 implant plus lipreading compared to lipreading alone for , en.., ." 70 all children except child 4 when given the BKB sentence ChIld 2 test. An improvement in lipreading alone scores from so ...... preoperative to postoperative testing was seen for children 40 I and 4 with the BKB sentence test. These latter findings 3D may have been due to a training and/or maturation effect. 20 The verbal children were also able to understand some speech with electrical stimulation alone and their results for AB words and BKB sentences are shown in Figure 11. '0 20 '0 The scores were higher for the AB words and ranged from 30070 to 43070. The results for BKB sentences ranged from 26070 to 34070. Not only did the verbal children have improvements in FIG. 13. Verbal responses for pre-verbal children measured over time speech perception and speech production but also with their post-implantation. language. The improvements in language over time for child I are shown in Figure 12 (Busby et ai, 1990). From this it As can be seen, the children's verbal responses increased can be seen how the observed scores get closer to the markedly following implantation. This is presumably due expected age appropriate scores following cochlear to auditory stimulation from the implant, but could also implantation. be due to a training effect. Further research is required to

1. OTOLARYNG. SOC. AUSTRAL., JANUARY 1991. 6, No.5 -- r------­ \ " CLARK, G.M. ET AL. 353

develop assessment procedures to determine the benefits processor for the 22 electrode Melbourne/Cochlear hearing prosthesis. of cochlear implants in pre-verbal children. Proceedings of the 14th World Congress of Otorhinolaryngology, Madrid, September, 1989, in press. GEERS, A .., MOOG, J. (1989) Factors Predictive of the Development Conclusion of Literacy in Profoundly Hearing Impaired Adolescents. Volta Review, 91, 69-85. In summary, we would emphasize that cochlear implants LUTERMAN, D. (1979) Counselling parents of hearing impaired help profoundly deaf children to communicate, but results children. Boston: Little, Brown and Co. vary. Auditory/oral training is essential, and our clinical WTERMAN, D. (1984) Counselling the communicatively disordered experience suggests that children will obtain better results and their friends. Boston: Little, Brown and Co. if they receive an implant at an early age. RICKARDS, F.W., CLARK, G.M. (1984) Steady-state evoked potentials to amplitude-modulated tones. In: Evoked Potentials II. Eds. Nodar R.H., Barber C. Butterworths, Boston, 163-168. Acknowledgement ROWLAND, L.C., DAWSON, P.W., DETTMAN, 5.J., BROWN, A.M., DOWELL, R.C., CLARK, G.M. (1990a) (Re) Habilitation Programme We would like to acknowledge the financial support from for Children Using the Cochlear 22-Electrode Multiple-Channel the National Health and Medical Research Council of Cochlear Implant. Human Communication Research Centre, Australia, Lions Clubs International, and the Deafness Department of Otolaryngology, University of Melbourne, and Cochlear Foundation of Victoria. Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia. Denver: Cochlear Corporation. ROWLAND, L.C., DETTMAN, S.J., CLARK, G.M. (l990b) Cochlear References implants in children: preliminary data on changes in caregiver-child interaction. In: A Summary of Professional Papers. Australian BUSBY, P.A., DETTMAN, S.J., ALTIDIS, P.M., BLAMEY, D.J., Association of Speech and Hearing. The 1990 Conference, p. 135. ROBERTS, S.A. (1990) Assessment of communication skills in SHEPHERD, R.K., XU, S.A., JONATHON, D.A., MATSUSHIMA, implanted deaf children. In: Cochlear Prostheses. Eds. Clark, G.M., J., NI, D., XU, 1.., FRANZ, B.K-H.G., CLARK, G.M., PURSER, S., Tong, Y.C., Patrick, J.E, Edinburgh, Churchill Livingstone, 223-235. MILLARD, R.E., TONG, Y.C., REDHEAD, T.l, KUZMA, J.A., DOWELL, R.C., DAWSON, P.W., DETTMAN, S.J., SHEPHERD, PATRICK, J.E (1989) Studies on Pediatric Auditory Prosthesis R.K., WHITFORD, L.A., SELIGMAN, P.M., CLARK, G.M. Implants. Tenth Quarterly Progress Report, National Institutes of Multichannel cochlear implantation in children: a summary of current Health Contract NOl·NS·7-2342. work at the University of Melbourne. Proceedings of the Third The New Encyclopaedia Britannica (1983) Vol 6: 15th Ed., pp. 432-433. Symposium on Cochlear Implants in Children, Indiana School of WEBB, R.L., PYMAN, B.E., FRANZ, B.K-H.G., CLARK, G.M. (1990) Medicine, January, 1990, in press. The surgery of cochlear implantation. In: Cochlear Prostheses. Eds. DOWELL, R.C., WHITFORD, L.A., SELIGMAN, P.M., FRANZ, Clark, G.M., Tong, Y.c., Patrick, J.E, Edinburgh: Churchill B.K-H.G., CLARK, G.M. Preliminary results with a miniature speech Livingstone, 153-179.

J. OTOLARYNG. SOC. AUSTRAL.. JANUARY 1991, 6, No.5

Minerva Access is the Institutional Repository of The University of Melbourne

Author/s: Dawson, Pam W.; Blamey, Peter J.; Dettman, Shani J.; Rowland, L.C.; Brown, A. M.; Dowell, Richard C.; Pyman, B. C.; Webb, R. L.

Title: Multi-channel cochlear implants for children: the Melbourne Program

Date: 1991

Citation: Clark, G. M., Dawson, P. W., Blamey, P. J., Dettman, S. J., Rowland, L., Brown, A. M., et al. (1991). Multi-channel cochlear implants for children: the Melbourne Program. Journal of the Otolaryngological Society of Australia, 6(5), 348-353.

Persistent Link: http://hdl.handle.net/11343/27298

File Description: Multi-channel cochlear implants for children: the Melbourne Program